Bio-Prospecting of a Few Brown Seaweeds for Their Cytotoxic and Antioxidant Activities
Methanolic extracts (MEs) of seven brown seaweeds occurring in the Indian coastal waters were screened for their cytotoxic and antioxidant properties following various assays. The methanolic extracts of seaweeds in the order ofDictyopteris australis > Spatoglossum variabile > Stoechospermum marginatum > Spatoglossum aspermumshowed significant cytotoxic activity. A very high DPPH radical scavenging activity was exhibited by the methanolic extracts prepared fromSt. marginatum, Padina tetrastromatica, Dictyopteris delicatulaandS. aspermum. The total phenolic content of the MEs varied from 13.19 ± 0.32 to 25.29 ± 0.445 gallic acid equivalents (mg g−1of methanolic extract). The reducing power assay indicated a dose dependency, at concentrations of 0.1, 0.5 and 1.0 and 2.0 mg mL−1of MEs and decreased in the following order:Butylated hydroxy toluene > P. tetrastromatica > D. delicatula > S. aspermum > S. variabile > S. marginatum > D. australis > S. marginatum. Furthermore,D. australis,S. aspermum, S. variabileandS. marginatumdemonstrated good metal ion chelating properties. All the above evidences suggest that, the antioxidant compounds found in brown seaweeds scavenge free radicals through effective intervention. This decisively promotes them as a potential source of natural antioxidants.